<!DOCTYPE html><html lang="zh-CN" data-theme="light"><head><meta charset="UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width,initial-scale=1,maximum-scale=1,user-scalable=no"><title>JS进阶第二天 | XC's Blog</title><meta name="keywords" content="JavaScript高级"><meta name="author" content="XC's Blog"><meta name="copyright" content="XC's Blog"><meta name="format-detection" content="telephone=no"><meta name="theme-color" content="#ffffff"><meta name="description" content="JavaScript进阶 – 第二天 了解面向对象编程的基础概念及构造函数的作用，体会 JavaScript 一切皆对象的语言特征，掌握常见的对象属性和方法的使用。   了解面向对象编程中的一般概念 能够基于构造函数创建对象 理解 JavaScript 中一切皆对象的语言特征 理解引用对象类型值存储的的特征 掌握包装类型对象常见方法的使用  深入对象 了解面向对象的基础概念，能够利用构造函数创建对"><meta property="og:type" content="article"><meta property="og:title" content="JS进阶第二天"><meta property="og:url" content="https://www.webxc.ml/post/us87/index.html"><meta property="og:site_name" content="XC&#39;s Blog"><meta property="og:description" content="JavaScript进阶 – 第二天 了解面向对象编程的基础概念及构造函数的作用，体会 JavaScript 一切皆对象的语言特征，掌握常见的对象属性和方法的使用。   了解面向对象编程中的一般概念 能够基于构造函数创建对象 理解 JavaScript 中一切皆对象的语言特征 理解引用对象类型值存储的的特征 掌握包装类型对象常见方法的使用  深入对象 了解面向对象的基础概念，能够利用构造函数创建对"><meta property="og:locale" content="zh_CN"><meta property="og:image" content="https://npm.elemecdn.com/webxc/cover/js1.webp"><meta property="article:published_time" content="2023-05-05T01:20:00.000Z"><meta property="article:modified_time" content="2023-05-04T17:24:22.255Z"><meta property="article:author" content="XC&#39;s Blog"><meta property="article:tag" content="JavaScript高级"><meta name="twitter:card" content="summary"><meta name="twitter:image" content="https://npm.elemecdn.com/webxc/cover/js1.webp"><link rel="shortcut icon" href="https://npm.elemecdn.com/webxc@1.0.0/logo/logo.jpg"><link rel="canonical" href="https://www.webxc.ml/post/us87/"><link rel="preconnect" href="//cdn.jsdelivr.net"><link rel="preconnect" href="//busuanzi.ibruce.info"><link rel="stylesheet" href="/css/index.css"><link rel="stylesheet" href="https://npm.elemecdn.com/@fortawesome/fontawesome-free@6.2.0/css/all.min.css" media="print" onload='this.media="all"'><link rel="stylesheet" href="https://npm.elemecdn.com/node-snackbar/dist/snackbar.min.css" media="print" onload='this.media="all"'><link rel="stylesheet" href="https://npm.elemecdn.com/@fancyapps/ui/dist/fancybox.css" media="print" onload='this.media="all"'><script>const GLOBAL_CONFIG={root:"/",algolia:void 0,localSearch:{path:"/search.xml",preload:!1,languages:{hits_empty:"找不到您查询的内容：${query}"}},translate:void 0,noticeOutdate:void 0,highlight:{plugin:"highlighjs",highlightCopy:!0,highlightLang:!0,highlightHeightLimit:!1},copy:{success:"吾辈宣布,你的剪切板已被占领",error:"呀~复制失败,请在尝试下",noSupport:"对不起,你的浏览器不支持"},relativeDate:{homepage:!1,post:!1},runtime:"",date_suffix:{just:"刚刚",min:"分钟前",hour:"小时前",day:"天前",month:"个月前"},copyright:{limitCount:60,languages:{author:"作者: XC's Blog",link:"链接: ",source:"来源: XC's Blog",info:"著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。"}},lightbox:"fancybox",Snackbar:{chs_to_cht:"您已切换为繁体",cht_to_chs:"您已切换为简体",day_to_night:"您已切换为深色主题",night_to_day:"您已切换为浅色主题",bgLight:"#3b70fc",bgDark:"#121212",position:"bottom-center"},source:{justifiedGallery:{js:"https://npm.elemecdn.com/flickr-justified-gallery/dist/fjGallery.min.js",css:"https://npm.elemecdn.com/flickr-justified-gallery/dist/fjGallery.css"}},isPhotoFigcaption:!1,islazyload:!0,isAnchor:!0}</script><script id="config-diff">var GLOBAL_CONFIG_SITE={title:"JS进阶第二天",isPost:!0,isHome:!1,isHighlightShrink:!1,isToc:!0,postUpdate:"2023-05-04 17:24:22"}</script><noscript><style>#nav{opacity:1}.justified-gallery img{opacity:1}#post-meta time,#recent-posts time{display:inline!important}</style></noscript><script>(e=>{e.saveToLocal={set:function(e,t,o){if(0===o)return;const n=864e5*o,a={value:t,expiry:(new Date).getTime()+n};localStorage.setItem(e,JSON.stringify(a))},get:function(e){const t=localStorage.getItem(e);if(!t)return;const o=JSON.parse(t);if(!((new Date).getTime()>o.expiry))return o.value;localStorage.removeItem(e)}},e.getScript=e=>new Promise(((t,o)=>{const n=document.createElement("script");n.src=e,n.async=!0,n.onerror=o,n.onload=n.onreadystatechange=function(){const e=this.readyState;e&&"loaded"!==e&&"complete"!==e||(n.onload=n.onreadystatechange=null,t())},document.head.appendChild(n)})),e.activateDarkMode=function(){document.documentElement.setAttribute("data-theme","dark"),null!==document.querySelector('meta[name="theme-color"]')&&document.querySelector('meta[name="theme-color"]').setAttribute("content","#0d0d0d")},e.activateLightMode=function(){document.documentElement.setAttribute("data-theme","light"),null!==document.querySelector('meta[name="theme-color"]')&&document.querySelector('meta[name="theme-color"]').setAttribute("content","#ffffff")};const t=saveToLocal.get("theme");"dark"===t?activateDarkMode():"light"===t&&activateLightMode();const o=saveToLocal.get("aside-status");void 0!==o&&("hide"===o?document.documentElement.classList.add("hide-aside"):document.documentElement.classList.remove("hide-aside"));/iPad|iPhone|iPod|Macintosh/.test(navigator.userAgent)&&document.documentElement.classList.add("apple")})(window)</script><link rel="stylesheet" href="https://cdn1.tianli0.top/gh/web-xc/My-blog-CSS/mgi.css"><link rel="stylesheet" href="https://cdn1.tianli0.top/gh/web-xc/My-blog-CSS/mg111.css"><link rel="stylesheet" href="https://npm.elemecdn.com/webxc@1.0.16/css/mg2.css"><link rel="stylesheet" href="https://npm.elemecdn.com/webxc@1.0.11/css/styless.css"><link rel="stylesheet" href="https://npm.elemecdn.com/webxc@1.0.11/css/styles.css"><link rel="stylesheet" href="https://npm.elemecdn.com/webxc@1.0.11/css/font.css"><link rel="stylesheet" href="https://npm.elemecdn.com/webxc@1.0.15/css/font2.css"><link rel="stylesheet" href="https://npm.elemecdn.com/webxc@1.0.12/css/swiper/swiper.min.css" media="print" onload='this.media="all"'><link rel="stylesheet" href="https://npm.elemecdn.com/webxc@1.0.12/css/swiper/swiperstyle.css" media="print" onload='this.media="all"'><meta name="generator" content="Hexo 6.3.0"></head><body><div id="sidebar"><div id="menu-mask"></div><div id="sidebar-menus"><div class="avatar-img is-center"><img src="https://npm.elemecdn.com/webxc@1.0.0/logo/logo.jpg" onerror='onerror=null,src="https://npm.elemecdn.com/webxc@1.0.2/banner/404.gif"' alt="avatar"></div><div class="sidebar-site-data site-data is-center"><a href="/archives/"><div class="headline">文章</div><div class="length-num">74</div></a><a href="/tags/"><div class="headline">标签</div><div class="length-num">22</div></a><a href="/categories/"><div class="headline">分类</div><div class="length-num">22</div></a></div><hr><div class="menus_items"><div class="menus_item"><a class="site-page" href="/"><i class="fa-fw iconfont icon-shouye"></i> <span>首页</span></a></div><div class="menus_item"><a class="site-page" href="/archives/"><i class="fa-fw iconfont icon-shijian"></i> <span>时间轴</span></a></div><div class="menus_item"><a class="site-page" href="/tags/"><i class="fa-fw iconfont icon-biaoqian"></i> <span>标签</span></a></div><div class="menus_item"><a class="site-page" href="/categories/"><i class="fa-fw iconfont icon-fenlei"></i> <span>分类</span></a></div><div class="menus_item"><a class="site-page" href="/link/"><i class="fa-fw iconfont icon-lianxiwomen"></i> <span>友联</span></a></div><div class="menus_item"><a class="site-page" href="/about/"><i class="fa-fw iconfont icon-iconzhengli-"></i> <span>关于</span></a></div><div class="menus_item"><a class="site-page group hide" href="javascript:void(0);"><i class="fa-fw iconfont icon-a-wangzhanchaojilianjiehulianwang"></i> <span>推荐</span><i class="fas fa-chevron-down"></i></a><ul class="menus_item_child"><li><a class="site-page child" target="_blank" rel="noopener" href="http://www.inode.club/"><i class="fa-fw fa-sharp fa-solid fa-square-rss"></i> <span>程序员指南</span></a></li><li><a class="site-page child" target="_blank" rel="noopener" href="http://ife.baidu.com/"><i class="fa-fw fa-brands fa-vuejs"></i> <span>前端技术学园</span></a></li><li><a class="site-page child" target="_blank" rel="noopener" href="https://www.yuque.com/tademanong/ag7q4n"><i class="fa-fw fa-solid fa-users"></i> <span>前端技术圈</span></a></li><li><a class="site-page child" target="_blank" rel="noopener" href="https://www.code-nav.cn/"><i class="fa-fw fa-solid fa-shop"></i> <span>编程导航</span></a></li><li><a class="site-page child" target="_blank" rel="noopener" href="https://q.shanyue.tech/"><i class="fa-fw fa-brands fa-square-js"></i> <span>每日一题</span></a></li><li><a class="site-page child" target="_blank" rel="noopener" href="https://fanyouf.gitee.io/u1word/#/h5"><i class="fa-fw fa-solid fa-headphones"></i> <span>前端必会单词</span></a></li><li><a class="site-page child" target="_blank" rel="noopener" href="https://site.51git.cn/render/gonav/4.html"><i class="fa-fw iconfont icon-wangzhandingzhi"></i> <span>网址导航</span></a></li><li><a class="site-page child" href="https://www.webxc.ml/music/"><i class="fa-fw iconfont icon-musical-note"></i> <span>音乐解锁</span></a></li></ul></div></div></div></div><div class="post" id="body-wrap"><header class="post-bg" id="page-header" style="background-image:url('https://npm.elemecdn.com/webxc/cover/js1.webp')"><nav id="nav"><span id="blog_name"><div class="back-home-button" tabindex="-1"><i class="back-home-button-icon fas fa-grip-vertical"></i><div class="back-menu-list-groups"><div class="back-menu-list-group"><div class="back-menu-list-title">项目</div><div class="back-menu-list"><a class="back-menu-item" href="/" title="前往博客主页" target="_blank" one-link-mark="yes"><img class="back-menu-item-icon" src="https://npm.elemecdn.com/webxc@1.0.0/logo/logo.jpg"><span class="back-menu-item-text">主站</span></a><a class="back-menu-item" href="https://e.webxc.tk/" rel="external nofollow" title="前往学习笔记" target="_blank" one-link-mark="yes"><img class="back-menu-item-icon" src="https://npm.elemecdn.com/webxc@1.0.0/logo/logo.jpg"><span class="back-menu-item-text">学习笔记</span></a><a class="back-menu-item" href="https://v.webxc.tk/" rel="external nofollow" title="VuePress学习文档" target="_blank" one-link-mark="yes"><img class="back-menu-item-icon" src="https://npm.elemecdn.com/webxc@1.0.0/logo/logo.jpg"><span class="back-menu-item-text">VuePress文档</span></a><a class="back-menu-item" href="https://b.webxc.tk/" rel="external nofollow" title="旧站Hexo" target="_blank" one-link-mark="yes"><img class="back-menu-item-icon" src="https://npm.elemecdn.com/webxc@1.0.0/logo/logo.jpg"><span class="back-menu-item-text">旧站Hexo</span></a><a class="back-menu-item" href="https://gridea.webxc.ml/" rel="external nofollow" title="Gridea笔记" target="_blank" one-link-mark="yes"><img class="back-menu-item-icon" src="https://npm.elemecdn.com/webxc@1.0.0/logo/logo.jpg"><span class="back-menu-item-text">Gridea笔记</span></a><a class="back-menu-item" href="https://c.webxc.tk/" rel="external nofollow" title="魔改Hexo" target="_blank" one-link-mark="yes"><img class="back-menu-item-icon" src="https://npm.elemecdn.com/webxc@1.0.0/logo/logo.jpg"><span class="back-menu-item-text">魔改Hexo</span></a></div></div><div class="back-menu-list-group"><div class="back-menu-list-title">博客镜像</div><div class="back-menu-list"><a class="back-menu-item" href="https://blog.webxc.ml/" title="Vercel镜像" target="_blank" rel="noopener nofollow" one-link-mark="yes"><img class="back-menu-item-icon" src="https://npm.elemecdn.com/webxc@1.0.0/logo/logo.jpg"><span class="back-menu-item-text">Vercel镜像</span></a><a class="back-menu-item" href="https://webxc.tk/" title="Netlify镜像" target="_blank" rel="noopener nofollow" one-link-mark="yes"><img class="back-menu-item-icon" src="https://npm.elemecdn.com/webxc@1.0.0/logo/logo.jpg"><span class="back-menu-item-text">Netlify镜像</span></a><a class="back-menu-item" href="https://web-xc.gitee.io/" title="Gitee镜像" target="_blank" rel="noopener nofollow" one-link-mark="yes"><img class="back-menu-item-icon" src="https://npm.elemecdn.com/webxc@1.0.0/logo/logo.jpg"><span class="back-menu-item-text">Gitee镜像</span></a><a class="back-menu-item" href="https://cf.webxc.ml/" title="Cloudflare镜像" target="_blank" rel="noopener nofollow" one-link-mark="yes"><img class="back-menu-item-icon" src="https://npm.elemecdn.com/webxc@1.0.0/logo/logo.jpg"><span class="back-menu-item-text">Cloudflare镜像</span></a><a class="back-menu-item" href="https://render.webxc.ml/" title="Render镜像" target="_blank" rel="noopener nofollow" one-link-mark="yes"><img class="back-menu-item-icon" src="https://npm.elemecdn.com/webxc@1.0.0/logo/logo.jpg"><span class="back-menu-item-text">Render镜像</span></a></div></div></div></div><a id="site-name" href="/"><div class="title">XC's Blog</div><i class="fa-solid fa-house"></i></a></span><div class="mask-name-container"><center id="name-container"><a id="page-name" href="javascript:btf.scrollToDest(0, 500)">PAGE_NAME</a></center></div><div id="menus"><div class="nav-button" id="search-button"><a class="site-page social-icon search"><i class="fas fa-search fa-fw"></i> <span>搜索</span></a></div><div class="nav-button" id="darkmode_navswitch"><a class="darkmode_switchbutton" type="button" title="浅色和深色模式转换" onclick="switchDarkMode()"><i class="fas fa-adjust"></i></a></div><div class="nav-button" id="nav-totop"><a class="totopbtn"><i class="fas fa-arrow-up"></i><span id="percent" onclick="btf.scrollToDest(0,500)">0</span></a></div><div class="menus_items"><div class="menus_item"><a class="site-page" href="/"><i class="fa-fw iconfont icon-shouye"></i> <span>首页</span></a></div><div class="menus_item"><a class="site-page" href="/archives/"><i class="fa-fw iconfont icon-shijian"></i> <span>时间轴</span></a></div><div class="menus_item"><a class="site-page" href="/tags/"><i class="fa-fw iconfont icon-biaoqian"></i> <span>标签</span></a></div><div class="menus_item"><a class="site-page" href="/categories/"><i class="fa-fw iconfont icon-fenlei"></i> <span>分类</span></a></div><div class="menus_item"><a class="site-page" href="/link/"><i class="fa-fw iconfont icon-lianxiwomen"></i> <span>友联</span></a></div><div class="menus_item"><a class="site-page" href="/about/"><i class="fa-fw iconfont icon-iconzhengli-"></i> <span>关于</span></a></div><div class="menus_item"><a class="site-page group hide" href="javascript:void(0);"><i class="fa-fw iconfont icon-a-wangzhanchaojilianjiehulianwang"></i> <span>推荐</span><i class="fas fa-chevron-down"></i></a><ul class="menus_item_child"><li><a class="site-page child" target="_blank" rel="noopener" href="http://www.inode.club/"><i class="fa-fw fa-sharp fa-solid fa-square-rss"></i> <span>程序员指南</span></a></li><li><a class="site-page child" target="_blank" rel="noopener" href="http://ife.baidu.com/"><i class="fa-fw fa-brands fa-vuejs"></i> <span>前端技术学园</span></a></li><li><a class="site-page child" target="_blank" rel="noopener" href="https://www.yuque.com/tademanong/ag7q4n"><i class="fa-fw fa-solid fa-users"></i> <span>前端技术圈</span></a></li><li><a class="site-page child" target="_blank" rel="noopener" href="https://www.code-nav.cn/"><i class="fa-fw fa-solid fa-shop"></i> <span>编程导航</span></a></li><li><a class="site-page child" target="_blank" rel="noopener" href="https://q.shanyue.tech/"><i class="fa-fw fa-brands fa-square-js"></i> <span>每日一题</span></a></li><li><a class="site-page child" target="_blank" rel="noopener" href="https://fanyouf.gitee.io/u1word/#/h5"><i class="fa-fw fa-solid fa-headphones"></i> <span>前端必会单词</span></a></li><li><a class="site-page child" target="_blank" rel="noopener" href="https://site.51git.cn/render/gonav/4.html"><i class="fa-fw iconfont icon-wangzhandingzhi"></i> <span>网址导航</span></a></li><li><a class="site-page child" href="https://www.webxc.ml/music/"><i class="fa-fw iconfont icon-musical-note"></i> <span>音乐解锁</span></a></li></ul></div></div><div id="toggle-menu"><a class="site-page"><i class="fas fa-bars fa-fw"></i></a></div></div></nav><div id="post-info"><h1 class="post-title">JS进阶第二天</h1><div id="post-meta"><div class="meta-firstline"><span class="post-meta-date"><i class="far fa-calendar-alt fa-fw post-meta-icon"></i><span class="post-meta-label">发表于</span><time class="post-meta-date-created" datetime="2023-05-05T01:20:00.000Z" title="发表于 2023-05-05 01:20:00">2023-05-05</time><span class="post-meta-separator">|</span><i class="fas fa-history fa-fw post-meta-icon"></i><span class="post-meta-label">更新于</span><time class="post-meta-date-updated" datetime="2023-05-04T17:24:22.255Z" title="更新于 2023-05-04 17:24:22">2023-05-04</time></span><span class="post-meta-categories"><span class="post-meta-separator">|</span><i class="fas fa-inbox fa-fw post-meta-icon"></i><a class="post-meta-categories" href="/categories/JavaScript%E9%AB%98%E7%BA%A7/">JavaScript高级</a></span></div><div class="meta-secondline"><span class="post-meta-separator">|</span><span data-flag-title="JS进阶第二天"><i class="far fa-eye fa-fw post-meta-icon"></i><span class="post-meta-label">阅读量:</span><span id="twikoo_visitors"><i class="fa-solid fa-spinner fa-spin"></i></span></span></div></div></div></header><main class="layout" id="content-inner"><div id="post"><article class="post-content" id="article-container"><h1 id="JavaScript进阶-–-第二天"><a href="#JavaScript进阶-–-第二天" class="headerlink" title="JavaScript进阶 – 第二天"></a>JavaScript进阶 – 第二天</h1><blockquote><p>了解面向对象编程的基础概念及构造函数的作用，体会 JavaScript 一切皆对象的语言特征，掌握常见的对象属性和方法的使用。</p></blockquote><ul><li>了解面向对象编程中的一般概念</li><li>能够基于构造函数创建对象</li><li>理解 JavaScript 中一切皆对象的语言特征</li><li>理解引用对象类型值存储的的特征</li><li>掌握包装类型对象常见方法的使用</li></ul><h2 id="深入对象"><a href="#深入对象" class="headerlink" title="深入对象"></a>深入对象</h2><blockquote><p>了解面向对象的基础概念，能够利用构造函数创建对象。</p></blockquote><h3 id="构造函数"><a href="#构造函数" class="headerlink" title="构造函数"></a>构造函数</h3><p>构造函数是专门用于创建对象的函数，如果一个函数使用 <code>new</code> 关键字调用，那么这个函数就是构造函数。</p><figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">script</span>&gt;</span><span class="language-javascript"></span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// 定义函数</span></span></span><br><span class="line"><span class="language-javascript">  <span class="keyword">function</span> <span class="title function_">foo</span>(<span class="params"></span>) &#123;</span></span><br><span class="line"><span class="language-javascript">    <span class="variable language_">console</span>.<span class="title function_">log</span>(<span class="string">&#x27;通过 new 也能调用函数...&#x27;</span>);</span></span><br><span class="line"><span class="language-javascript">  &#125;</span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// 调用函数</span></span></span><br><span class="line"><span class="language-javascript">  <span class="keyword">new</span> foo;</span></span><br><span class="line"><span class="language-javascript"></span><span class="tag">&lt;/<span class="name">script</span>&gt;</span></span><br></pre></td></tr></table></figure><p>总结：</p><ol start="2"><li>使用 <code>new</code> 关键字调用函数的行为被称为实例化</li><li>实例化构造函数时没有参数时可以省略 <code>()</code></li><li>构造函数的返回值即为新创建的对象</li><li>构造函数内部的 <code>return</code> 返回的值无效！</li></ol><p>注：实践中为了从视觉上区分构造函数和普通函数，习惯将构造函数的首字母大写。</p><h3 id="实例成员"><a href="#实例成员" class="headerlink" title="实例成员"></a>实例成员</h3><p>通过构造函数创建的对象称为实例对象，实例对象中的属性和方法称为实例成员。</p><figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">script</span>&gt;</span><span class="language-javascript"></span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// 构造函数</span></span></span><br><span class="line"><span class="language-javascript">  <span class="keyword">function</span> <span class="title function_">Person</span>(<span class="params"></span>) &#123;</span></span><br><span class="line"><span class="language-javascript">    <span class="comment">// 构造函数内部的 this 就是实例对象</span></span></span><br><span class="line"><span class="language-javascript">    <span class="comment">// 实例对象中动态添加属性</span></span></span><br><span class="line"><span class="language-javascript">    <span class="variable language_">this</span>.<span class="property">name</span> = <span class="string">&#x27;小明&#x27;</span></span></span><br><span class="line"><span class="language-javascript">    <span class="comment">// 实例对象动态添加方法</span></span></span><br><span class="line"><span class="language-javascript">    <span class="variable language_">this</span>.<span class="property">sayHi</span> = <span class="keyword">function</span> (<span class="params"></span>) &#123;</span></span><br><span class="line"><span class="language-javascript">      <span class="variable language_">console</span>.<span class="title function_">log</span>(<span class="string">&#x27;大家好~&#x27;</span>)</span></span><br><span class="line"><span class="language-javascript">    &#125;</span></span><br><span class="line"><span class="language-javascript">  &#125;</span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// 实例化，p1 是实例对象</span></span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// p1 实际就是 构造函数内部的 this</span></span></span><br><span class="line"><span class="language-javascript">  <span class="keyword">const</span> p1 = <span class="keyword">new</span> <span class="title class_">Person</span>()</span></span><br><span class="line"><span class="language-javascript">  <span class="variable language_">console</span>.<span class="title function_">log</span>(p1)</span></span><br><span class="line"><span class="language-javascript">  <span class="variable language_">console</span>.<span class="title function_">log</span>(p1.<span class="property">name</span>) <span class="comment">// 访问实例属性</span></span></span><br><span class="line"><span class="language-javascript">  p1.<span class="title function_">sayHi</span>() <span class="comment">// 调用实例方法</span></span></span><br><span class="line"><span class="language-javascript"></span><span class="tag">&lt;/<span class="name">script</span>&gt;</span></span><br></pre></td></tr></table></figure><p>总结：</p><ol><li>构造函数内部 <code>this</code> 实际上就是实例对象，为其动态添加的属性和方法即为实例成员</li><li>为构造函数传入参数，动态创建结构相同但值不同的对象</li></ol><p>注：构造函数创建的实例对象彼此独立互不影响。</p><h3 id="静态成员"><a href="#静态成员" class="headerlink" title="静态成员"></a>静态成员</h3><p>在 JavaScript 中底层函数本质上也是对象类型，因此允许直接为函数动态添加属性或方法，构造函数的属性和方法被称为静态成员。</p><figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">script</span>&gt;</span><span class="language-javascript"></span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// 构造函数</span></span></span><br><span class="line"><span class="language-javascript">  <span class="keyword">function</span> <span class="title function_">Person</span>(<span class="params">name, age</span>) &#123;</span></span><br><span class="line"><span class="language-javascript">    <span class="comment">// 省略实例成员</span></span></span><br><span class="line"><span class="language-javascript">  &#125;</span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// 静态属性</span></span></span><br><span class="line"><span class="language-javascript">  <span class="title class_">Person</span>.<span class="property">eyes</span> = <span class="number">2</span></span></span><br><span class="line"><span class="language-javascript">  <span class="title class_">Person</span>.<span class="property">arms</span> = <span class="number">2</span></span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// 静态方法</span></span></span><br><span class="line"><span class="language-javascript">  <span class="title class_">Person</span>.<span class="property">walk</span> = <span class="keyword">function</span> (<span class="params"></span>) &#123;</span></span><br><span class="line"><span class="language-javascript">    <span class="variable language_">console</span>.<span class="title function_">log</span>(<span class="string">&#x27;^_^人都会走路...&#x27;</span>)</span></span><br><span class="line"><span class="language-javascript">    <span class="comment">// this 指向 Person</span></span></span><br><span class="line"><span class="language-javascript">    <span class="variable language_">console</span>.<span class="title function_">log</span>(<span class="variable language_">this</span>.<span class="property">eyes</span>)</span></span><br><span class="line"><span class="language-javascript">  &#125;</span></span><br><span class="line"><span class="language-javascript"></span><span class="tag">&lt;/<span class="name">script</span>&gt;</span></span><br></pre></td></tr></table></figure><p>总结：</p><ol><li>静态成员指的是添加到构造函数本身的属性和方法</li><li>一般公共特征的属性或方法静态成员设置为静态成员</li><li>静态成员方法中的 <code>this</code> 指向构造函数本身</li></ol><h2 id="内置构造函数"><a href="#内置构造函数" class="headerlink" title="内置构造函数"></a>内置构造函数</h2><blockquote><p>掌握各引用类型和包装类型对象属性和方法的使用。</p></blockquote><p>在 JavaScript 中<strong>最主要</strong>的数据类型有 6 种，分别是字符串、数值、布尔、undefined、null 和 对象，常见的对象类型数据包括数组和普通对象。其中字符串、数值、布尔、undefined、null 也被称为简单类型或基础类型，对象也被称为引用类型。</p><p>在 JavaScript 内置了一些构造函数，绝大部的数据处理都是基于这些构造函数实现的，JavaScript 基础阶段学习的 <code>Date</code> 就是内置的构造函数。</p><figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">script</span>&gt;</span><span class="language-javascript"></span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// 实例化</span></span></span><br><span class="line"><span class="language-javascript">	<span class="keyword">let</span> date = <span class="keyword">new</span> <span class="title class_">Date</span>();</span></span><br><span class="line"><span class="language-javascript">  </span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// date 即为实例对象</span></span></span><br><span class="line"><span class="language-javascript">  <span class="variable language_">console</span>.<span class="title function_">log</span>(date);</span></span><br><span class="line"><span class="language-javascript"></span><span class="tag">&lt;/<span class="name">script</span>&gt;</span></span><br></pre></td></tr></table></figure><p>甚至字符串、数值、布尔、数组、普通对象也都有专门的构造函数，用于创建对应类型的数据。</p><h3 id="Object"><a href="#Object" class="headerlink" title="Object"></a>Object</h3><p><code>Object</code> 是内置的构造函数，用于创建普通对象。</p><figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">script</span>&gt;</span><span class="language-javascript"></span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// 通过构造函数创建普通对象</span></span></span><br><span class="line"><span class="language-javascript">  <span class="keyword">const</span> user = <span class="keyword">new</span> <span class="title class_">Object</span>(&#123;<span class="attr">name</span>: <span class="string">&#x27;小明&#x27;</span>, <span class="attr">age</span>: <span class="number">15</span>&#125;)</span></span><br><span class="line"><span class="language-javascript"></span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// 这种方式声明的变量称为【字面量】</span></span></span><br><span class="line"><span class="language-javascript">  <span class="keyword">let</span> student = &#123;<span class="attr">name</span>: <span class="string">&#x27;杜子腾&#x27;</span>, <span class="attr">age</span>: <span class="number">21</span>&#125;</span></span><br><span class="line"><span class="language-javascript">  </span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// 对象语法简写</span></span></span><br><span class="line"><span class="language-javascript">  <span class="keyword">let</span> name = <span class="string">&#x27;小红&#x27;</span>;</span></span><br><span class="line"><span class="language-javascript">  <span class="keyword">let</span> people = &#123;</span></span><br><span class="line"><span class="language-javascript">    <span class="comment">// 相当于 name: name</span></span></span><br><span class="line"><span class="language-javascript">    name,</span></span><br><span class="line"><span class="language-javascript">    <span class="comment">// 相当于 walk: function () &#123;&#125;</span></span></span><br><span class="line"><span class="language-javascript">    walk () &#123;</span></span><br><span class="line"><span class="language-javascript">      <span class="variable language_">console</span>.<span class="title function_">log</span>(<span class="string">&#x27;人都要走路...&#x27;</span>);</span></span><br><span class="line"><span class="language-javascript">    &#125;</span></span><br><span class="line"><span class="language-javascript">  &#125;</span></span><br><span class="line"><span class="language-javascript"></span></span><br><span class="line"><span class="language-javascript">  <span class="variable language_">console</span>.<span class="title function_">log</span>(student.<span class="property">constructor</span>);</span></span><br><span class="line"><span class="language-javascript">  <span class="variable language_">console</span>.<span class="title function_">log</span>(user.<span class="property">constructor</span>);</span></span><br><span class="line"><span class="language-javascript">  <span class="variable language_">console</span>.<span class="title function_">log</span>(student <span class="keyword">instanceof</span> <span class="title class_">Object</span>);</span></span><br><span class="line"><span class="language-javascript"></span><span class="tag">&lt;/<span class="name">script</span>&gt;</span></span><br></pre></td></tr></table></figure><p>。</p><p>总结：</p><ol><li>推荐使用字面量方式声明对象，而不是 <code>Object</code> 构造函数</li><li><code>Object.assign</code> 静态方法创建新的对象</li><li><code>Object.keys</code> 静态方法获取对象中所有属性</li><li><code>Object.values</code> 表态方法获取对象中所有属性值</li></ol><h3 id="Array"><a href="#Array" class="headerlink" title="Array"></a>Array</h3><p><code>Array</code> 是内置的构造函数，用于创建数组。</p><figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">script</span>&gt;</span><span class="language-javascript"></span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// 构造函数创建数组</span></span></span><br><span class="line"><span class="language-javascript">  <span class="keyword">let</span> arr = <span class="keyword">new</span> <span class="title class_">Array</span>(<span class="number">5</span>, <span class="number">7</span>, <span class="number">8</span>);</span></span><br><span class="line"><span class="language-javascript"></span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// 字面量方式创建数组</span></span></span><br><span class="line"><span class="language-javascript">  <span class="keyword">let</span> list = [<span class="string">&#x27;html&#x27;</span>, <span class="string">&#x27;css&#x27;</span>, <span class="string">&#x27;javascript&#x27;</span>]</span></span><br><span class="line"><span class="language-javascript"></span></span><br><span class="line"><span class="language-javascript"></span><span class="tag">&lt;/<span class="name">script</span>&gt;</span></span><br></pre></td></tr></table></figure><p>数组赋值后，无论修改哪个变量另一个对象的数据值也会相当发生改变。</p><p>总结：</p><ol><li><p>推荐使用字面量方式声明数组，而不是 <code>Array</code> 构造函数</p></li><li><p>实例方法 <code>forEach</code> 用于遍历数组，替代 <code>for</code> 循环 (重点)</p></li><li><p>实例方法 <code>filter</code> 过滤数组单元值，生成新数组(重点)</p></li><li><p>实例方法 <code>map</code> 迭代原数组，生成新数组(重点)</p></li><li><p>实例方法 <code>join</code> 数组元素拼接为字符串，返回字符串(重点)</p></li><li><p>实例方法 <code>find</code> 查找元素， 返回符合测试条件的第一个数组元素值，如果没有符合条件的则返回 undefined(重点)</p></li><li><p>实例方法<code>every</code> 检测数组所有元素是否都符合指定条件，如果<strong>所有元素</strong>都通过检测返回 true，否则返回 false(重点)</p></li><li><p>实例方法<code>some</code> 检测数组中的元素是否满足指定条件 <strong>如果数组中有</strong>元素满足条件返回 true，否则返回 false</p></li><li><p>实例方法 <code>concat</code> 合并两个数组，返回生成新数组</p></li><li><p>实例方法 <code>sort</code> 对原数组单元值排序</p></li><li><p>实例方法 <code>splice</code> 删除或替换原数组单元</p></li><li><p>实例方法 <code>reverse</code> 反转数组</p></li><li><p>实例方法 <code>findIndex</code> 查找元素的索引值</p><p>​</p></li></ol><h3 id="包装类型"><a href="#包装类型" class="headerlink" title="包装类型"></a>包装类型</h3><p>在 JavaScript 中的字符串、数值、布尔具有对象的使用特征，如具有属性和方法，如下代码举例：</p><figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">script</span>&gt;</span><span class="language-javascript"></span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// 字符串类型</span></span></span><br><span class="line"><span class="language-javascript">  <span class="keyword">const</span> str = <span class="string">&#x27;hello world!&#x27;</span></span></span><br><span class="line"><span class="language-javascript"> 	<span class="comment">// 统计字符的长度（字符数量）</span></span></span><br><span class="line"><span class="language-javascript">  <span class="variable language_">console</span>.<span class="title function_">log</span>(str.<span class="property">length</span>)</span></span><br><span class="line"><span class="language-javascript">  </span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// 数值类型</span></span></span><br><span class="line"><span class="language-javascript">  <span class="keyword">const</span> price = <span class="number">12.345</span></span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// 保留两位小数</span></span></span><br><span class="line"><span class="language-javascript">  price.<span class="title function_">toFixed</span>(<span class="number">2</span>) <span class="comment">// 12.34</span></span></span><br><span class="line"><span class="language-javascript"></span><span class="tag">&lt;/<span class="name">script</span>&gt;</span></span><br></pre></td></tr></table></figure><p>之所以具有对象特征的原因是字符串、数值、布尔类型数据是 JavaScript 底层使用 Object 构造函数“包装”来的，被称为包装类型。</p><h4 id="String"><a href="#String" class="headerlink" title="String"></a>String</h4><p><code>String</code> 是内置的构造函数，用于创建字符串。</p><figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">script</span>&gt;</span><span class="language-javascript"></span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// 使用构造函数创建字符串</span></span></span><br><span class="line"><span class="language-javascript">  <span class="keyword">let</span> str = <span class="keyword">new</span> <span class="title class_">String</span>(<span class="string">&#x27;hello world!&#x27;</span>);</span></span><br><span class="line"><span class="language-javascript"></span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// 字面量创建字符串</span></span></span><br><span class="line"><span class="language-javascript">  <span class="keyword">let</span> str2 = <span class="string">&#x27;你好，世界！&#x27;</span>;</span></span><br><span class="line"><span class="language-javascript"></span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// 检测是否属于同一个构造函数</span></span></span><br><span class="line"><span class="language-javascript">  <span class="variable language_">console</span>.<span class="title function_">log</span>(str.<span class="property">constructor</span> === str2.<span class="property">constructor</span>); <span class="comment">// true</span></span></span><br><span class="line"><span class="language-javascript">  <span class="variable language_">console</span>.<span class="title function_">log</span>(str <span class="keyword">instanceof</span> <span class="title class_">String</span>); <span class="comment">// false</span></span></span><br><span class="line"><span class="language-javascript"></span><span class="tag">&lt;/<span class="name">script</span>&gt;</span></span><br></pre></td></tr></table></figure><p>总结：</p><ol><li>实例属性 <code>length</code> 用来获取字符串的度长(重点)</li><li>实例方法 <code>split(&#39;分隔符&#39;)</code> 用来将字符串拆分成数组(重点)</li><li>实例方法 <code>substring（需要截取的第一个字符的索引[,结束的索引号]）</code> 用于字符串截取(重点)</li><li>实例方法 <code>startsWith(检测字符串[, 检测位置索引号])</code> 检测是否以某字符开头(重点)</li><li>实例方法 <code>includes(搜索的字符串[, 检测位置索引号])</code> 判断一个字符串是否包含在另一个字符串中，根据情况返回 true 或 false(重点)</li><li>实例方法 <code>toUpperCase</code> 用于将字母转换成大写</li><li>实例方法 <code>toLowerCase</code> 用于将就转换成小写</li><li>实例方法 <code>indexOf</code> 检测是否包含某字符</li><li>实例方法 <code>endsWith</code> 检测是否以某字符结尾</li><li>实例方法 <code>replace</code> 用于替换字符串，支持正则匹配</li><li>实例方法 <code>match</code> 用于查找字符串，支持正则匹配</li></ol><p>注：String 也可以当做普通函数使用，这时它的作用是强制转换成字符串数据类型。</p><h4 id="Number"><a href="#Number" class="headerlink" title="Number"></a>Number</h4><p><code>Number</code> 是内置的构造函数，用于创建数值。</p><figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">script</span>&gt;</span><span class="language-javascript"></span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// 使用构造函数创建数值</span></span></span><br><span class="line"><span class="language-javascript">  <span class="keyword">let</span> x = <span class="keyword">new</span> <span class="title class_">Number</span>(<span class="string">&#x27;10&#x27;</span>)</span></span><br><span class="line"><span class="language-javascript">  <span class="keyword">let</span> y = <span class="keyword">new</span> <span class="title class_">Number</span>(<span class="number">5</span>)</span></span><br><span class="line"><span class="language-javascript"></span></span><br><span class="line"><span class="language-javascript">  <span class="comment">// 字面量创建数值</span></span></span><br><span class="line"><span class="language-javascript">  <span class="keyword">let</span> z = <span class="number">20</span></span></span><br><span class="line"><span class="language-javascript"></span></span><br><span class="line"><span class="language-javascript"></span><span class="tag">&lt;/<span class="name">script</span>&gt;</span></span><br></pre></td></tr></table></figure><p>总结：</p><ol><li>推荐使用字面量方式声明数值，而不是 <code>Number</code> 构造函数</li><li>实例方法 <code>toFixed</code> 用于设置保留小数位的长度</li></ol></article><div class="post-copyright"><div class="post-copyright__author"><span class="post-copyright-meta">本文作者:</span> <span class="post-copyright-info"><a href="https://www.webxc.ml">XC's Blog</a></span></div><div class="post-copyright__type"><span class="post-copyright-meta">本文链接:</span> <span class="post-copyright-info"><a href="https://www.webxc.ml/post/us87/">https://www.webxc.ml/post/us87/</a></span></div><div class="post-copyright__notice"><span class="post-copyright-meta">版权声明:</span> <span class="post-copyright-info">本博客所有文章除特别声明外，均采用 <a href="https://creativecommons.org/licenses/by-nc-sa/4.0/" target="_blank">CC BY-NC-SA 4.0</a> 许可协议。转载请注明来自 <a href="https://www.webxc.ml" target="_blank">XC's Blog</a>！</span></div></div><div class="tag_share"><div class="post-meta__tag-list"><a class="post-meta__tags" href="/tags/JavaScript%E9%AB%98%E7%BA%A7/">JavaScript高级</a></div><div class="post_share"><div class="social-share" data-image="https://npm.elemecdn.com/webxc/cover/js1.webp" data-sites="facebook,twitter,wechat,weibo,qq"></div><link rel="stylesheet" href="https://npm.elemecdn.com/butterfly-extsrc/sharejs/dist/css/share.min.css" media="print" onload='this.media="all"'><script src="https://npm.elemecdn.com/butterfly-extsrc/sharejs/dist/js/social-share.min.js" defer></script></div></div><div class="post-reward"><div class="reward-button"><i class="fas fa-qrcode"></i> 打赏</div><div class="reward-main"><ul class="reward-all"><li class="reward-item"><a href="https://npm.elemecdn.com/webxc@1.0.0/lxfs/wechat.png" target="_blank"><img class="post-qr-code-img" src="https://npm.elemecdn.com/webxc@1.0.0/lxfs/wechat.png" alt="Wechat"></a><div class="post-qr-code-desc">Wechat</div></li><li class="reward-item"><a href="https://npm.elemecdn.com/webxc@1.0.0/lxfs/alipay.jpg" target="_blank"><img class="post-qr-code-img" src="https://npm.elemecdn.com/webxc@1.0.0/lxfs/alipay.jpg" alt="Alipay"></a><div class="post-qr-code-desc">Alipay</div></li></ul></div></div><nav class="pagination-post" id="pagination"><div class="prev-post pull-full"><a href="/post/re67/"><img class="prev-cover" src="https://npm.elemecdn.com/webxc/cover/js1.webp" onerror='onerror=null,src="https://npm.elemecdn.com/webxc@1.0.2/banner/404.gif"' alt="cover of previous post"><div class="pagination-info"><div class="label">上一篇文章</div><div class="prev_info">JS进阶第一天</div></div></a></div></nav><div class="relatedPosts"><div class="headline"><i class="fas fa-thumbs-up fa-fw"></i><span>相关推荐</span></div><div class="relatedPosts-list"><div><a href="/post/re67/" title="JS进阶第一天"><img class="cover" src="https://npm.elemecdn.com/webxc/cover/js1.webp" alt="cover"><div class="content is-center"><div class="date"><i class="far fa-calendar-alt fa-fw"></i> 2023-04-26</div><div class="title">JS进阶第一天</div></div></a></div></div></div><hr><div id="post-comment"><div class="comment-head"><div class="comment-headline"><i class="fas fa-comments fa-fw"></i> <span>评论</span></div></div><div class="comment-wrap"><div><div id="twikoo-wrap"></div></div></div></div></div><div class="aside-content" id="aside-content"><div class="card-widget card-info"><div class="is-center"><div class="avatar-img"><img src="https://npm.elemecdn.com/webxc@1.0.0/logo/logo.jpg" onerror='this.onerror=null,this.src="https://npm.elemecdn.com/webxc@1.0.2/banner/404.gif"' alt="avatar"></div><div class="author-info__name">XC's Blog</div><div class="author-info__description">XC's Blog 记录生活和学习文章</div></div><div class="card-info-data site-data is-center"><a href="/archives/"><div class="headline">文章</div><div class="length-num">74</div></a><a href="/tags/"><div class="headline">标签</div><div class="length-num">22</div></a><a href="/categories/"><div class="headline">分类</div><div class="length-num">22</div></a></div><div class="card-info-social-icons is-center"><a class="social-icon" href="https://tenapi.cn/qqzlk/?qq=2848141597" target="_blank" title="QQ"><i class="iconfont icon-QQ"></i></a><a class="social-icon" href="https://npm.elemecdn.com/webxc@1.0.0/lxfs/wechat.jpg" target="_blank" title="微信"><i class="iconfont icon-weixin"></i></a><a class="social-icon" href="https://github.com/web-xc" target="_blank" title="Github"><i class="iconfont icon-github"></i></a><a class="social-icon" href="https://space.bilibili.com/2134826455" target="_blank" title="BiliBili"><i class="iconfont icon-bilibili"></i></a><a class="social-icon" href="https://music.163.com/#/user/home?id=323682437" target="_blank" title="网易云音乐"><i class="iconfont icon-wyy"></i></a></div></div><div class="sticky_layout"><div class="card-widget" id="card-toc"><div class="item-headline"><i class="fas fa-stream"></i><span>目录</span><span class="toc-percentage"></span></div><div class="toc-content"><ol class="toc"><li class="toc-item toc-level-1"><a class="toc-link" href="#JavaScript%E8%BF%9B%E9%98%B6-%E2%80%93-%E7%AC%AC%E4%BA%8C%E5%A4%A9"><span class="toc-number">1.</span> <span class="toc-text">JavaScript进阶 – 第二天</span></a><ol class="toc-child"><li class="toc-item toc-level-2"><a class="toc-link" href="#%E6%B7%B1%E5%85%A5%E5%AF%B9%E8%B1%A1"><span class="toc-number">1.1.</span> <span class="toc-text">深入对象</span></a><ol class="toc-child"><li class="toc-item toc-level-3"><a class="toc-link" href="#%E6%9E%84%E9%80%A0%E5%87%BD%E6%95%B0"><span class="toc-number">1.1.1.</span> <span class="toc-text">构造函数</span></a></li><li class="toc-item toc-level-3"><a class="toc-link" href="#%E5%AE%9E%E4%BE%8B%E6%88%90%E5%91%98"><span class="toc-number">1.1.2.</span> <span class="toc-text">实例成员</span></a></li><li class="toc-item toc-level-3"><a class="toc-link" href="#%E9%9D%99%E6%80%81%E6%88%90%E5%91%98"><span class="toc-number">1.1.3.</span> <span class="toc-text">静态成员</span></a></li></ol></li><li class="toc-item toc-level-2"><a class="toc-link" href="#%E5%86%85%E7%BD%AE%E6%9E%84%E9%80%A0%E5%87%BD%E6%95%B0"><span class="toc-number">1.2.</span> <span class="toc-text">内置构造函数</span></a><ol class="toc-child"><li class="toc-item toc-level-3"><a class="toc-link" href="#Object"><span class="toc-number">1.2.1.</span> <span class="toc-text">Object</span></a></li><li class="toc-item toc-level-3"><a class="toc-link" href="#Array"><span class="toc-number">1.2.2.</span> <span class="toc-text">Array</span></a></li><li class="toc-item toc-level-3"><a class="toc-link" href="#%E5%8C%85%E8%A3%85%E7%B1%BB%E5%9E%8B"><span class="toc-number">1.2.3.</span> <span class="toc-text">包装类型</span></a><ol class="toc-child"><li class="toc-item toc-level-4"><a class="toc-link" href="#String"><span class="toc-number">1.2.3.1.</span> <span class="toc-text">String</span></a></li><li class="toc-item toc-level-4"><a class="toc-link" href="#Number"><span class="toc-number">1.2.3.2.</span> <span class="toc-text">Number</span></a></li></ol></li></ol></li></ol></li></ol></div></div><div class="card-widget card-recent-post"><div class="item-headline"><i class="fas fa-history"></i><span>最新文章</span></div><div class="aside-list"><div class="aside-list-item"><a class="thumbnail" href="/post/us87/" title="JS进阶第二天"><img src="https://npm.elemecdn.com/webxc/cover/js1.webp" onerror='this.onerror=null,this.src="https://npm.elemecdn.com/webxc@1.0.2/banner/404.gif"' alt="JS进阶第二天"></a><div class="content"><a class="title" href="/post/us87/" title="JS进阶第二天">JS进阶第二天</a><time datetime="2023-05-05T01:20:00.000Z" title="发表于 2023-05-05 01:20:00">2023-05-05</time></div></div><div class="aside-list-item"><a class="thumbnail" href="/post/re67/" title="JS进阶第一天"><img src="https://npm.elemecdn.com/webxc/cover/js1.webp" onerror='this.onerror=null,this.src="https://npm.elemecdn.com/webxc@1.0.2/banner/404.gif"' alt="JS进阶第一天"></a><div class="content"><a class="title" href="/post/re67/" title="JS进阶第一天">JS进阶第一天</a><time datetime="2023-04-26T16:30:00.000Z" title="发表于 2023-04-26 16:30:00">2023-04-26</time></div></div><div class="aside-list-item"><a class="thumbnail" href="/post/ar34/" title="Web APIs第七天"><img src="https://cdn1.tianli0.top/gh/web-xc/iMG/postss/webapis.jpg" onerror='this.onerror=null,this.src="https://npm.elemecdn.com/webxc@1.0.2/banner/404.gif"' alt="Web APIs第七天"></a><div class="content"><a class="title" href="/post/ar34/" title="Web APIs第七天">Web APIs第七天</a><time datetime="2023-04-17T20:00:00.000Z" title="发表于 2023-04-17 20:00:00">2023-04-17</time></div></div></div></div></div></div></main><footer id="footer"><div id="footer-wrap"><div class="copyright">&copy;2021 - 2023 By XC's Blog</div><div class="framework-info"><span></span> <a target="_blank" rel="noopener" href="https://icp.gov.moe/?keyword=20235221">萌ICP备20235221号</a><span class="footer-separator">|</span><span></span> <a target="_blank" rel="noopener" href="https://icp.gov.moe/">萌ICP查询</a><div id="running-time"></div></div><script>setInterval((()=>{let e=Math.round(new Date("2021-11-21 01:35:06").getTime()/1e3),t=Math.round(((new Date).getTime()+288e5)/1e3)-e,n=new Array(0,0,0,0,0);t>=31536e3&&(n[0]=parseInt(t/31536e3),t%=31536e3),t>=86400&&(n[1]=parseInt(t/86400),t%=86400),t>=3600&&(n[2]=parseInt(t/3600),t%=3600),t>=60&&(n[3]=parseInt(t/60),t%=60),t>0&&(n[4]=t),currentTimeHtml="本站已安全运行 "+n[0]+" 年 "+n[1]+" 天 "+n[2]+" 时 "+n[3]+" 分 "+n[4]+" 秒",document.getElementById("running-time").innerHTML=currentTimeHtml}),1e3)</script></div></footer></div><div id="rightside"><div id="rightside-config-hide"><button id="readmode" type="button" title="阅读模式"><i class="fas fa-book-open"></i></button><button id="darkmode" type="button" title="浅色和深色模式转换"><i class="fas fa-adjust"></i></button><button id="hide-aside-btn" type="button" title="单栏和双栏切换"><i class="fas fa-arrows-alt-h"></i></button></div><div id="rightside-config-show"><button id="rightside_config" type="button" title="设置"><i class="fas fa-cog fa-spin"></i></button><button class="close" id="mobile-toc-button" type="button" title="目录"><i class="fas fa-list-ul"></i></button><a id="to_comment" href="#post-comment" title="直达评论"><i class="fas fa-comments"></i></a><button id="go-up" type="button" title="回到顶部"><i class="fas fa-arrow-up"></i><span id="percent">0<span>%</span></span></button><button id="go-down" type="button" title="直达底部" onclick="btf.scrollToDest(document.body.scrollHeight,500)"><i class="fas fa-arrow-down"></i></button></div></div><div id="local-search"><div class="search-dialog"><nav class="search-nav"><span class="search-dialog-title">搜索</span><span id="loading-status"></span><button class="search-close-button"><i class="fas fa-times"></i></button></nav><div class="is-center" id="loading-database"><i class="fas fa-spinner fa-pulse"></i> <span>正在载入文件,请稍后</span></div><div class="search-wrap"><div id="local-search-input"><div class="local-search-box"><input class="local-search-box--input" placeholder="搜索文章" type="text"></div></div><hr><div id="local-search-results"></div></div></div><div id="search-mask"></div></div><div><script src="https://npm.elemecdn.com/hexo-theme-butterfly/source/js/utils.js"></script><script src="https://npm.elemecdn.com/hexo-theme-butterfly@4.4.0/source/js/main.js"></script><script src="https://npm.elemecdn.com/@fancyapps/ui/dist/fancybox.umd.js"></script><script src="https://npm.elemecdn.com/vanilla-lazyload/dist/lazyload.iife.min.js"></script><script src="https://npm.elemecdn.com/node-snackbar/dist/snackbar.min.js"></script><script src="https://npm.elemecdn.com/hexo-theme-butterfly/source/js/search/local-search.js"></script><div class="js-pjax"><script>(()=>{const e=document.querySelectorAll("#article-container .mermaid-wrap");if(e.length){window.runMermaid=()=>{window.loadMermaid=!0;const t="dark"===document.documentElement.getAttribute("data-theme")?"dark":"default";Array.from(e).forEach(((e,n)=>{const d=e.firstElementChild,r="mermaid-"+n,m="%%{init:{ 'theme':'"+t+"'}}%%\n"+d.textContent;mermaid.mermaidAPI.render(r,m,(e=>{d.insertAdjacentHTML("afterend",e)}))}))};const t=()=>{window.loadMermaid?runMermaid():getScript("https://npm.elemecdn.com/mermaid/dist/mermaid.min.js").then(runMermaid)};window.pjax?t():document.addEventListener("DOMContentLoaded",t)}})()</script><script>(()=>{const o=()=>{twikoo.init(Object.assign({el:"#twikoo-wrap",envId:"https://blog2.webxc.ml/",region:"",onCommentLoaded:function(){btf.loadLightbox(document.querySelectorAll("#twikoo .tk-content img:not(.tk-owo-emotion)"))}},null))},t=()=>{"object"!=typeof twikoo?getScript("https://npm.elemecdn.com/twikoo@1.6.10/dist/twikoo.all.min.js").then(o):setTimeout(o,0)};t()})()</script></div><script data-pjax="true" defer src="https://npm.elemecdn.com/webxc@1.0.16/css/style.js"></script><script defer src="https://npm.elemecdn.com/hexo-theme-butterfly@4.4.0/source/js/search/local-search.js"></scrip><script src="https://npm.elemecdn.com/butterfly-extsrc/dist/activate-power-mode.min.js"></script><script>POWERMODE.colorful=!0,POWERMODE.shake=!0,POWERMODE.mobile=!0,document.body.addEventListener("input",POWERMODE)</script><script src="https://npm.elemecdn.com/pjax@0.2.8/pjax.min.js"></script><script>let pjaxSelectors=["head > title","#config-diff","#body-wrap","#rightside-config-hide","#rightside-config-show",".js-pjax",".tk-comments-container"];var pjax=new Pjax({elements:'a:not([target="_blank"])',selectors:pjaxSelectors,cacheBust:!1,analytics:!1,scrollRestoration:!1});document.addEventListener("pjax:send",(function(){if(window.tocScrollFn&&window.removeEventListener("scroll",window.tocScrollFn),window.scrollCollect&&window.removeEventListener("scroll",scrollCollect),"object"==typeof preloader&&preloader.initLoading(),document.getElementById("rightside").style.cssText="opacity: ''; transform: ''",window.aplayers)for(let e=0;e<window.aplayers.length;e++)window.aplayers[e].options.fixed||window.aplayers[e].destroy();"object"==typeof typed&&typed.destroy();const e=document.body.classList;e.contains("read-mode")&&e.remove("read-mode"),"object"==typeof disqusjs&&disqusjs.destroy()})),document.addEventListener("pjax:complete",(function(){window.refreshFn(),document.querySelectorAll("script[data-pjax]").forEach((e=>{const t=document.createElement("script"),o=e.text||e.textContent||e.innerHTML||"";Array.from(e.attributes).forEach((e=>t.setAttribute(e.name,e.value))),t.appendChild(document.createTextNode(o)),e.parentNode.replaceChild(t,e)})),GLOBAL_CONFIG.islazyload&&window.lazyLoadInstance.update(),"function"==typeof chatBtnFn&&chatBtnFn(),"function"==typeof panguInit&&panguInit(),"function"==typeof gtag&&gtag("config","",{page_path:window.location.pathname}),"object"==typeof _hmt&&_hmt.push(["_trackPageview",window.location.pathname]),"function"==typeof loadMeting&&document.getElementsByClassName("aplayer").length&&loadMeting(),"object"==typeof Prism&&Prism.highlightAll(),"object"==typeof preloader&&preloader.endLoading()})),document.addEventListener("pjax:error",(e=>{404===e.request.status&&pjax.loadUrl("/404.html")}))</script><script async data-pjax src="//busuanzi.ibruce.info/busuanzi/2.3/busuanzi.pure.mini.js"></script></div><script data-pjax>function butterfly_swiper_injector_config(){var s=document.getElementById("recent-posts");console.log("已挂载butterfly_swiper"),s.insertAdjacentHTML("afterbegin",'<div class="recent-post-item" style="height: auto;width: 100%"><div class="blog-slider swiper-container-fade swiper-container-horizontal" id="swiper_container"><div class="blog-slider__wrp swiper-wrapper" style="transition-duration: 0ms;"><div class="blog-slider__item swiper-slide" style="background:url(https://cdn1.tianli0.top/gh/web-xc/iMG/postss/webapis.jpg);border-radius:12px;opacity: 1; transform: translate3d(0px, 0px, 0px); transition-duration: 0ms;"><div class="blog-slider__content"><span class="blog-slider__code">2023-04-11</span><a class="blog-slider__title" onclick="pjax.loadUrl(&quot;post/fr67/&quot;);" href="javascript:void(0);" alt="">Web APIs第六天</a><div class="blog-slider__text">点击查看</div></div></div><div class="blog-slider__item swiper-slide" style="background:url(https://npm.elemecdn.com/webxc/cover/js1.webp);border-radius:12px;opacity: 1; transform: translate3d(0px, 0px, 0px); transition-duration: 0ms;"><div class="blog-slider__content"><span class="blog-slider__code">2023-02-16</span><a class="blog-slider__title" onclick="pjax.loadUrl(&quot;post/fd38/&quot;);" href="javascript:void(0);" alt="">JavaScript 第五天</a><div class="blog-slider__text">点击查看</div></div></div><div class="blog-slider__item swiper-slide" style="background:url(https://npm.elemecdn.com/webxc/cover/js1.webp);border-radius:12px;opacity: 1; transform: translate3d(0px, 0px, 0px); transition-duration: 0ms;"><div class="blog-slider__content"><span class="blog-slider__code">2023-02-07</span><a class="blog-slider__title" onclick="pjax.loadUrl(&quot;post/7f86/&quot;);" href="javascript:void(0);" alt="">JavaScript 第四天</a><div class="blog-slider__text">点击查看</div></div></div><div class="blog-slider__item swiper-slide" style="background:url(https://npm.elemecdn.com/webxc/cover/js1.webp);border-radius:12px;opacity: 1; transform: translate3d(0px, 0px, 0px); transition-duration: 0ms;"><div class="blog-slider__content"><span class="blog-slider__code">2022-12-27</span><a class="blog-slider__title" onclick="pjax.loadUrl(&quot;post/6e+47/&quot;);" href="javascript:void(0);" alt="">JavaScript 第三天</a><div class="blog-slider__text">点击查看</div></div></div><div class="blog-slider__item swiper-slide" style="background:url(https://npm.elemecdn.com/webxc@1.0.12/cover/cover15.jpg);border-radius:12px;opacity: 1; transform: translate3d(0px, 0px, 0px); transition-duration: 0ms;"><div class="blog-slider__content"><span class="blog-slider__code">2022-10-31</span><a class="blog-slider__title" onclick="pjax.loadUrl(&quot;post/2db5/&quot;);" href="javascript:void(0);" alt="">移动开发-Flex布局</a><div class="blog-slider__text">点击查看</div></div></div><div class="blog-slider__item swiper-slide" style="background:url(https://npm.elemecdn.com/webxc@1.0.12/cover/cover16.jpg);border-radius:12px;opacity: 1; transform: translate3d(0px, 0px, 0px); transition-duration: 0ms;"><div class="blog-slider__content"><span class="blog-slider__code">2022-11-14</span><a class="blog-slider__title" onclick="pjax.loadUrl(&quot;post/1c7e/&quot;);" href="javascript:void(0);" alt="">移动开发-媒体查询</a><div class="blog-slider__text">点击查看</div></div></div><div class="blog-slider__item swiper-slide" style="background:url(https://npm.elemecdn.com/webxc@1.0.12/cover/cover17.jpg);border-radius:12px;opacity: 1; transform: translate3d(0px, 0px, 0px); transition-duration: 0ms;"><div class="blog-slider__content"><span class="blog-slider__code">2022-11-17</span><a class="blog-slider__title" onclick="pjax.loadUrl(&quot;post/7fc/&quot;);" href="javascript:void(0);" alt="">移动开发-响应式</a><div class="blog-slider__text">点击查看</div></div></div><div class="blog-slider__item swiper-slide" style="background:url(https://npm.elemecdn.com/webxc@1.0.11/cover/css5.jpg);border-radius:12px;opacity: 1; transform: translate3d(0px, 0px, 0px); transition-duration: 0ms;"><div class="blog-slider__content"><span class="blog-slider__code">2022-10-16</span><a class="blog-slider__title" onclick="pjax.loadUrl(&quot;post/d97/&quot;);" href="javascript:void(0);" alt="">CSS-2D-3D转换</a><div class="blog-slider__text">点击查看</div></div></div></div><div class="blog-slider__pagination swiper-pagination-clickable swiper-pagination-bullets"></div><div class="swiper-button-prev"></div><div class="swiper-button-next"></div></div></div>')}for(var elist="null".split(","),cpage=location.pathname,epage="all",flag=0,i=0;i<elist.length;i++)cpage.includes(elist[i])&&flag++;("all"===epage&&0==flag||epage===cpage)&&butterfly_swiper_injector_config()</script><script defer src="https://npm.elemecdn.com/webxc@1.0.12/css/swiper/swiper.min.js"></script><script defer data-pjax src="https://npm.elemecdn.com/webxc@1.0.12/css/swiper/swiper_init.js"></script></body></html>